Monitoring of the Effects of Additives on Sludge Separation Properties by Using Sensors

Abstract

Two novel sensors, Settlometer and Sehlumosed, were used to evaluate the beneficial effect of three additives on sludge‐settling properties. Four different activated sludges were used in the study. The settling characteristics of the sludges were evaluated in automated batch settling tests by means of the start‐up time (initial lag period), initial settling velocity, stirred sludge volume, and final transparency of the supernatant. Different sludges responded in distinct ways to the dosage of additives. Talc was typically more effective than coal in terms of improving settling velocity and reducing sludge volume. Chemical polymer surpassed the two particulate additives in terms of final transparency. Furthermore, different sludge sedimentation parameters of a particular sludge were not affected to the same extent by a specific additive. This substantiates the need to describe settling properties with more than one parameter. The absolute values of the sedimentation properties were found to depend on the type of sensor used.